With a lot of old hard drives to test as working and clean up, I decided to use an old Dell (800mHz0 pc for the job. The hard drive in it was a 20G with WIN ME on it. It boots just fine. I replaced the hard drive with subsequent test drives, went into BIOS to tell it to detect the new drive. I get two results. Some drives are just invisible, nothing shows in IDE configuration. With others, I immediately get the message that the cpu is overheating and the pc will be shut down. I can boot to a floppy or a WIN98SE boot disk (cd) but trying to read the hard drive brings up Invalid Drive. Can anyone solve this mystery for me? Or is it as a friend says, a DELL thing.:confused:

HDDs are so generic that I cant believe its a "DELL thing". Perhaps the CPU really is too hot or the BIOS setup is such as to prompt you with a message at a very low threshold.

Using very large drives on older PCs can give odd results but, notwithstanding this fact and if the system is not really overheating, it would look likely to be some sort of motherboard hardware failure.

If the BIOS setup ever looks dodgey it is often a good first principle to change the CMOS battery and set the BIOS to failsafe defaults and ensure that the IDE controllers are set to autodetect.

Afterthought.

If you were to try these drives with a modern USB enclosure or converter cable it would save you having to open up the case and would at the same time remove any BIOS size limitations since modern hardware would all be 48bit-LBA compatible; it would also avoid any stress on the PSU or any worries about the internal connections or cables. Just ensure they are jumpered as masters.

Would the ATA rating of each drive versus the controller/mobo be significant I wonder? :confused:

The drives are all small, largest being a 40G. No one has donated an external enclosure yet but I'd try that if I could. :) I checked to see that the fan was operational and it is. The fact that it works well with the original drive has me confused. If one drive works, they all should or so I thought. I changed the CMOS battery before starting and checked all the BIOS settings then.

If the drives are not showing in the BIOS setup they are either intrinsically bad or else probably incorrectly jumpered for whatever cofiguration you are using. You may also need to manaully update some of the BIOS setup settings (notably autodetection of the drive geometry), if only by entering and exiting the CMOS settings on some systems.

If your system is overheating that needs the first attention.

I found that if I connect a questionable HD as the slave, the Dell is happy. ??? I need to post with a different question as I am having difficulties with getting a partition removed.